Heading into the 4th of July weekend, Connecticut drivers may find highways as crowded here as anywhere in the U.S. What they're also going to encounter is the fifth-worst bridges.

The state's highways are ranked third busiest. Connecticut ties for fifth nationally with 8 percent of its bridges considered structurally deficient, putting it in a tie with Michigan.

Highway congestion is increasing on the Interstate Highway System as travel increases faster than new capacity is added. More than two out of every five miles of the nation's urban interstates are congested. Travel on the interstate system surged in 2015 and early 2016, according to the national transportation research group Trip. It says the country's interstate highways represent 2.5 percent of all roadway lane miles in the U.S., but carry 25 percent of all vehicle travel in the nation.

Forty-three percent of the nation's urban interstate highways (8,020 of 18,567 miles) are considered congested because they carry traffic levels that result in significant delays during peak travel hours.

The 10 states with the greatest share of their urban interstate highways considered congested are California, Maryland, New Jersey, Rhode Island, Delaware, Massachusetts, Hawaii, Connecticut, Florida and Minnesota.

The state with the busiest urban interstates is California, where the average lane mile of urban interstate carried 19,424 vehicles per day in 2014. The five states with the busiest urban interstates are California, Maryland (18,425), Connecticut (15,391), Rhode Island (15,281) and Florida (15,088).

Rhode Island ranks highest when it comes to deficient bridges at 15 percent. It's followed by West Virginia and Wyoming, 9 percent; New York at 8 percent; and, Connecticut and Michigan at 7 percent.